| Specificity |
Ability to measure analyte without interference from impurities |
Inject blank, placebo, sample. Check peak purity with DAD spectra |
Resolution ≥2.0 between target peptide and nearest peak; peak purity angle < purity threshold |
| Linearity |
Proportional relationship between concentration and detector response |
5 concentration levels (50 – 150% of target), n=3 per level |
Correlation coefficient R² ≥0.999 |
| Accuracy |
Closeness of measured value to true value |
Spike known amount of reference standard at 80, 100, 120% of target |
Recovery 98.0 – 102.0% |
| Repeatability |
Precision under same conditions (same day, analyst, instrument) |
6 replicate injections of same sample |
Area RSD ≤1.0%; Retention time RSD ≤0.5% |
| Intermediate Precision |
Precision under different conditions |
Different analyst, different day, n=6 each |
RSD ≤2.0% across all results |
| LOD |
Limit of detection |
S/N measurement at low concentration |
S/N ≥3:1 |
| LOQ |
Limit of quantification |
S/N measurement at low concentration; n=6 injection precision |
S/N ≥10:1; RSD ≤20% |
| Robustness |
Resistance to deliberate parameter changes |
Vary flow (±0.1 mL/min), column temp (±2 °C), pH (±0.1), wavelength (±2 nm) |
%Change from original ≤2.0% |